I did the boiled rice and chicken diet to many times...and it never helped my dog. I did switch the chicken to ground beef and rinsed and drained the fat out of it and that worked better for my dog. So thats an option as well.
There is also a product called Karbo Essentials that you can give your dog mixed in their food. Its a great product and it helps your dog boost the way they digest their food. You can read more about it at The Xtra Scoop ~ Karbo Combo, Karbo Essentials, Epic II CL, Immune Builders & Supplements for Horses, Cattle, Dogs, Cats, and more!
I agree with adding probiotics to your dogs diet as well.